[daip] CLCOR SU table update problem (?)

[Lincoln Greenhill]

Dear Leonia,

Following our earlier email exchange, I made a test run of CLCOR w/
appropriate documentation. I still believe there is a problem with the
J2000 coordinates listed in the SU table after an update via ANTP.

Summary:  The apparent coordinates are updated correctly.
          The J2000 coordinates are not.  Differences in J2000
             coordinates before and after running CLCOR are too
             large in both RA and DEC, by factors of a few.  This
             is not possible.  

I agree with you that a proper implenentation of ANTP should proceed as
follows:


  CLCORPRM(4 and 5) + apriori apparent coordinate
                          |
                          |
         Precess & Nutate from epoch to J2000
                          |
                          |
                         \ /
                  New J2000 coordinate

For small angle changes in coordinates, the difference in J2000
coordinates (new-old) should be approximately the offset added to 
the apparent coordinates, with only a second order perturbation
caused by the implementation of precession/nutation algorithms.

                 J2000 (RA/DEC)                   Apparent
Apriori    5 35 14.5098  -5 22 30.48200   05 35 16.29728  -5 22 34.78376
Offset                                          +0.02"          +0.02"
New        5 35 14.50292 -5 22 30.31338   05 35 16.29862  -5 22 34.76376
--------   ----------------------------   ------------------------------
Difference      -0.10"         +0.17"
                 ^^^^           ^^^^
                  |              |
              TOO BIG         TOO BIG



Does AIPS correct for general relativity in the context of the solar
position?


Regards,

Lincoln